The answer lies within the amazing process of meiosis.

答案就在惊人的减数分裂过程中。

Then there is Meiosis for our gametes, because they (gametes) are different.

然后是配子减数分裂，因为它们（配子）是不同的。

During the first cellular division called meiosis I, the chromosomal pairs are separated.

细胞分裂，即减数分裂后，配对的同源分离。

During meiosis, one cell divides twice to form four daughter cells.

在减数分裂过程中，细胞分裂两，形成四子细胞。

The end result of meiosis 2 is production of four haploid cells, n chromosomes; (23 in humans) .

减数分裂 2 的最终结果是产生 4 单倍细胞，n 条；(人类为 23 条)。

But right around birth, the oocytes stop developing — they get stuck in the first stage of meiosis.

但是在出生的时候，卵母细胞停止发育——它们卡在减数分裂的阶段。

In the second cellular division called meiosis II, the sister chromatids of a given chromosome are separated.

二细胞分裂，也就是二减数分裂后，每的姐妹单分离。

They then rush through meiosis II, and their resulting daughter cells total four round spermatids.

然后它们快速通过减数分裂 II，它们产生的子细胞总共有四圆形精子细胞。

These primary spermatocytes then go into meiosis I, and form two smaller haploid cells called secondary spermatocytes.

这些初级精母细胞随后进入减数分裂期，形成两较小的单倍细胞，称为级精母细胞。

These structures are critical for the process of cell division in next step at meiosis 1.

这些结构对减数分裂 1 的下步细胞分裂过程至关重要。

The four main steps of meiosis 2 are: prophase 2, metaphase 2, anaphase 2, and telophase 2.

减数分裂 2 的四主要步骤是：前期 2、中期 2、后期 2 和末期 2。

Here are the distinct phases of meiosis: INTERPHASE MEIOSIS 1 CYTOKINESIS 1 MEIOSIS 2 CYTOKINESIS 2.

减数分裂的不同阶段是：间期，减数分裂 1，胞质分裂 1，减数分裂 2，胞质分裂 2。

Now we can go straight onto meiosis and the Kreb cycle.

现在我们可以直接进入减数分裂和克雷布循环。

To put it simply, during meiosis, the process in which gametes[3] are created, chromosomal crossover occurs.

简而言之，在减数分裂过程中， 即产生配子 [3] 的过程中，会发生交叉。

Meiosis 1 takes place in following steps: Prophase 1 Prophase 1 is typically the longest phase of meiosis.

减数分裂 1 按以下步骤进行：前期 1前期 1 通常是减数分裂的最长时期。

To do this, the primary oocytes have to complete meiosis 1, and in a person's lifetime only about 400 successfully do that.

要变成配子就必须要经历减数分裂，而人的生中大概只有400初级卵母细胞可以做到。

Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information.

减数分裂是分裂过程，单细胞分裂两，产生四细胞，其中包含半的原始遗传信息。

The secondary oocyte stops in metaphase of meiosis 2, and waits for fertilization as the menstrual cycle transitions into the luteal phase.

级卵泡会在二减数分裂中期停止分裂，并且在卵泡期向黄期转换的时候等待受精。

Now, only if and when an egg fuses with a sperm does it actually complete meiosis II and officially become an ovum.

现在，只有当卵子与精子融合时，它才真正完成减数分裂 II 并正式成为卵子。

The other option is the sister chromatids of the x chromosome don't separate in meiosis two in the female germ cell.

女性生殖细胞中，X姐妹单在二减数分裂时没有分离。